Physiological and biochemical characteristics of a manganese catalase lacking n-terminal

Abstract:

Abstract:［Objective］ We characterizeda manganese catalase lacking n-terminal (MnCAT-C)，to revealits roles in bacterial growth，reactive oxygen species (ROS) removal and degradation of polychlorinated biphenyls (PCBs) in Rhodococcus sp. R04．［Methods］Manganese catalase (Mn-CAT) sequence of the strain R04 was aligned with that of Rhodococcus sp. R1101．Mn-CAT and MnCAT-C were expressed in E．coli BL21 (DE3)，and the target protein was purified with Q-sepharose and ammonium sulphate precipitation．Knockout strain was obtained by homologous recombination. ROS was measured by fluorescence polarization，and the degradation rate of PCBs was measured by HPLC．［Results］ MnCAT-C protein was purified，and SDS-PAGE analysis showed that its molecular weight was 23 kDa．Compared with wild strains，the ROS concentration increased，and the growth rate was inhibited in knockout strains．Moreover，the degradationrate of PCBs decreased．［Conclusion］MnCAT-C retained the majority of the active properties of the original enzyme，including ROS clearance．The lack of MnCAT-C gene affected the growth rate and the PCBsdegradationrate instrain R04.